A comparative study on the measurement properties of Dermatology Life Quality Index (DLQI), DLQI‐Relevant and Skindex‐16*

Abstract

Background Dermatology Life Quality Index (DLQI) and Skindex-16 are among the most commonly used dermatology-specific health-related quality-of-life (HRQoL) instruments. DLQI has two common scoring methods, the original and the DLQI-Relevant (DLQI-R) modification. Head-to-head comparisons of the measurement properties of the DLQI, DLQI-R and Skindex-16 are currently lacking. Objectives We aim to compare the measurement properties of the DLQI, DLQI-R and Skindex-16. Methods We analysed data from 618 patients with self-reported physiciandiagnosed dermatological conditions from a cross-sectional survey carried out in Hungary in early 2020. DLQI, DLQI-R and Skindex-16 were compared in terms of ceiling and floor effects, informativity, convergent validity and known-group validity.Results Mean DLQI, DLQI-R and Skindex-16 total scores were 3Á76 AE 5Á03, 4Á11 AE 5Á34 and 29Á36 AE 26Á62, respectively. Among patients with a DLQI/ DLQI-R total score of zero, 64% reported problems on Skindex-16. Overall, 23-38% of patients with 'not relevant' responses on DLQI items 3 (shopping/ home/gardening), 7 (working/studying), 8 (interpersonal problems) and 9 (sexual difficulties) reported problems on their corresponding Skindex-16 items. Average relative informativity (Shannon's evenness index) was the highest for Skindex-16 (0Á85), followed by DLQI-R (0Á66) and DLQI (0Á54). DLQI, DLQI-R and Skindex-16 demonstrated similar convergent validity. DLQI was able to better discriminate between known groups of patients based on overall skin-related HRQoL impairment, whereas DLQI-R and Skindex-16 performed better with respect to self-perceived health status. Conclusions Skindex-16 seems to be more sensitive than DLQI/DLQI-R in capturing mild impairment in HRQoL. Our findings help to provide a fuller understanding of the difference between DLQI, DLQI-R and Skindex-16 and support the informed choice of instrument for clinical and research purposes.What is already known about this topic?• Dermatology Life Quality Index (DLQI) and Skindex-16 are among the most commonly used dermatology-specific instruments to measure health-related quality of life (HRQoL). DLQI has an alternative scoring, DLQI-Relevant (DLQI-R), developed in 2018. • So far, no studies have provided a comprehensive head-to-head comparison of the measurement properties of the DLQI, DLQI-R and Skindex-16.

Questionnaire use depends on the study goal, target group and phase of the condition

“…Such differences in questionnaire use are also reflected in the present study in this issue of the BJD 2 . Szabó et al .…”

“…Such differences in questionnaire use are also reflected in the present study in this issue of the BJD . 2 Szabó et al . compare the Dermatology Life Quality Index (DLQI), DLQI‐Relevant and Skindex‐19.…”

General and Skin-Specific Health-Related Quality of Life in Patients With Atopic Dermatitis Before and During the COVID-19 Pandemic

“…Based on our study, Skindex-16, DLQI, and DLQI-R also have good convergent and known-group validity in AD that make them appropriate instruments for HRQoL assessment in both clinical and research settings. Users are suggested to select measure(s) that best suit to their needs, taking into account the differences in content, length, and response scales between DLQI/DLQI-R and Skindex-16 74 . Moreover, this study also provides EQ-5D-5L utilities stratified according to severity groups (Table 4) that are considered useful as input data in economic evaluations of AD treatments.…”

Safety in numbers: risankizumab for moderate‐to‐severe psoriasis

“…1 Risankizumaba humanized monoclonal antibody that inhibits interleukin (IL)-23, a key cytokine in the pathogenesis of psoriasisis effective for treatment of psoriasis and Crohn disease. [2][3][4][5][6] In this issue of the BJD, Gordon et al report on the safety of risankizumab by analysing data from 17 completed or ongoing trials in patients with plaque psoriasis. 7 Adverse events were reported as exposure-adjusted event rates (EAERs) per 100 patient-years (PY).…”

“…1 Such differences in questionnaire use are also reflected in the present study in this issue of the BJD. 2 Szab o et al compare the Dermatology Life Quality Index (DLQI), DLQI-Relevant and Skindex-19. The DLQI is the most well-known, easy-touse and validated questionnaire in many countries, with extended norms for many skin conditions.…”